Liquid proportioning system

ABSTRACT

The specification and drawings disclose embodiments of a liquid proportioning apparatus which provides an exactly proportioned mixture of two liquids. The disclosed apparatus uses a pair of pistons which are interconnected such that one serves to drive the other. The driving piston is actuated by one of the liquids under pressure. The other piston acts to pump the second liquid. An adjustable lost motion connection between the two pistons allows the relative length of stroke of the two pistons to be varied.

United States Patent [191 Meister et al.

[ Mar. 26, 1974 LIQUID PROPORTIONING SYSTEM [75] Inventors: Harry M. Meister, 7640 Carmen Dr., N.W., Canton, Ohio 44720; James B. Kelley, Cleveland Heights; Gordon E. Holmes, Chagrin Falls, both of Ohio [73] Assignee: said Meister, by said Kelley and Holmes [22] Filed: Oct. 16, 1972 [21] Appl. No.: 298,004

[52] US. Cl. ZZZ/129.2 [51] Int. Cl. B67d 5/56 [58] Field of Search 222/129.2, 249, 129.4,

[56] References Cited UNITED STATES PATENTS Waite et a1. ZZZ/129.2 X

3/1966 Webber et al. 259/4 X 1/1951 Luster ZZZ/129.2

Primary ExaminerStanley H. Tollberg Attorney, Agent, or Firm-Fay, Sharpe and Mulholland [57] ABSTRACT The specification and drawings disclose embodiments of a liquid proportioning apparatus which provides an exactly proportioned mixture of two liquids. The disclosed apparatus uses a pair of pistons which are interconnected such that one serves to drive the other. The driving piston is actuated by one of the liquids under pressure. The other piston acts to pump the second liquid. An adjustable lost motion connection between the two pistons allows the relative length of stroke of the two pistons to be varied.

13 Claims, 3 Drawing Figures Pmmsumzs m4 3799.402

SHEET 2 [1F 3 LIQUID PROPORTIONING SYSTEM BACKGROUND OF THE INVENTION The subject invention is directed toward the art of 5 proportioning devices and, more particularly, to an improved apparatus for producing exactly proportioned fluid mixtures.

The invention is particularly suited for proportioning mixtures of water and release agents in the casting industry and will be described with particular reference thereto; however, as will become apparent, the invention is capable of much broader application and can be used whenever it is desired to provide an exactly proportioned fluid mixture.

Generally, prior to the present invention, fluid mixtures of the type under consideration were proportioned through the use of venturi-type fluid mixing and proportioning systems. The problem with the prior art proportioning devices was, primarily, that small changes in the pressure of the fluids supplied to the proportioning device would produce substantial variations in relative proportions. Additionally, the devices were sometimes impossible and, at best, difficult to readjust for varying the relative proportions of the fluids. Often, to change proportions required a completely new mixing assembly or a removal and replacement of orifice plates or the like. Consequently, as can readily be appreciated, there has been a distinct need for a positive, simple and reliable fluid proportioning device which assures exact relative proportions irrespective of the fluid supply pressures. Moreover, there has been a need for a device of this type which can be readily adjusted to produce varying mixture proportions without complex readjustments or substitution of major components.

BRIEF STATEMENT OF THE INVENTION In general, the invention contemplates an apparatus for closely proportioning at least a first and a second liquid through the use of a first double acting cylinder which is drivingly connected with a second cylinder, preferably a single acting cylinder. The first fluid is supplied under pressure to the first cylinder. Control means are associated with the assembly so that the first fluid is alternately supplied to opposite sides of the piston of the first cylinder to produce reciprocation thereof. Simultaneously, the fluid on the opposite side of the piston of the first cylinder is discharged. The second cylinder is connected through suitable supply and discharge lines with a source of second fluid. The supply and discharge lines for the second cylinder are arranged to permit the second cylinder to act as a pump. As can be appreciated, the first fluid serves as the power fluid for pumping the second fluid. Because the double acting cylinder has a positive displacement, and, because the second cylinder likewise has a positive displacement, movement of the first cylinder produces fixed relative proportions of discharge of first and second-fluid from the first and second cylinders. Preferrably, the discharged fluids are supplied to mixing means wherein they are intermixed.

It is also preferred that the connecting means between the first cylinder and the second cylinder comprise an adjustable means wherein the length of the reciprocation of the second cylinder can be varied relative to the length of the reciprocation of the second cylinder. This provides an adjustable relative proportion of the two fluids since a full stroke of the first cylinder can be arranged to produce only a partial stroke of the second cylinder. In a desirable form of the device, the adjusting means are a relatively simple, lost motion connection.

The invention also contemplates that the means used to control the supply of first fluid to the first cylinder will include a pilot valve which is controlled by a second valve alternately opened and closed by movement of the first piston.

In accordance with a somewhat more limited aspect of the invention, the pilot valve is a fluid actuated valve which is actuated by air or by the first fluid. This arrangement permits all controls for the assembly to be simple fluid actuated controls without the necessity of any electrical connections which could be dangerous in certain environments. However, it should be appreciated that electrical controls could be used in connection with certain applications, and the invention is therefor to be limited only by the language of the claims.

OBJECTS OF THE INVENTION Accordingly, a primary object of the invention is the provision of a highly accurate and adjustable fluid proportioning apparatus which is simple to construct and highly reliable in operation.

A somewhat more limited object of the invention is the provision of a system of the general type described in which one of the liquids being proportioned serves as the power and control fluid for the apparatus.

A still further object of the invention is the provision of a system of the general type described wherein the fluids or liquids are proportioned through the use of positive displacement cylinders adjustably interconnected so as to permit variations in the relative quanti- BRIEF DESCRIPTION OF THE DRAWINGS The above and other objects and advantages will become apparent from the following description when read in conjunction with the accompanying drawings wherein:

FIG. 1 is a somewhat diagrammatic showing of the preferred embodiment of the invention;

FIG. 2 is a diagrammatic showing of a second embodiment of the invention; and

FIG. 3 shows a typical installation utilizing a proportioning apparatus formed in accordance with the subject invention.

Referring more particularly to FIG. 1 of the drawings the overall arrangement of the invention can be readily understood. In general, the apparatus of FIG. I includes a first double acting fluid cylinder 10 which is drivingly interconnected with a second cylinder 12 by adjustable interconnecting means 14. Cylinder 10 serves as a power means for the unit and has its piston rod 16 drivingly connected to the piston rod 18 of cylinder l2. Cylinder 12 acts as a positive displacement pump for pumping and discharging exact quantities of one of the liquids being proportioned.

Referring more specially to the first double acting cylinder 10, it will be noted that supply and discharge means connect cylinder 10 with a pressurized source 22 of a first fluid, as well as, connecting it with a mixing means 24. Although the first fluid could be of many types, in the subject embodiment, it is water and the supply means 22 can simply be a pressurized water line. The water is supplied through a line 26 including a shutoff valve 28 and a filter 30 to a pilot or control valve 32. Valve 32 is a standard spool-type control valve which is adapted to be moved in one direction by a spring and in the opposite direction by fluid pressure. It serves to direct the supply of pressurized water from line 26 to opposite sides of the piston of cylinder 10 by shifting the water supply between lines 34 and 36. In the solid line position shown in FIG. 1, water is being supplied from line 26 to line 34 to thereby produce movement of cylinder 10s piston to the right. Simultaneously therewith, line 36 is connected with line 40 which leads to the mixing means 24. Consequently, as can be seen, during the period the fluid is being supplied through line 34 to cylinder 10, the fluid on the opposite side of the piston is being discharged to the mixing means. Upon shifting of the pilot valve 32 in the opposite direction (to the left as viewed in FIG. 1) the fluid from line 26 is directed to line 36 causing the piston to move to the left. Simultaneously therewith fluid from the left hand side of the piston is directed from line 34 to line 42 which also leads to the mixing means 24. Although shown as separate lines, lines 40 and 42 could be connected as a common line if desired.

Referring more specifically to the single acting cylinder 12 it will be noted that it has a single line 44 which is connected to a source 46 of a second liquid such as, for example, a release agent which needs to be mixed in a predetermined relative proportion with water. The line 44 includes a check valve 48 arranged to permit flow only in the direction of the arrow. Between check valve 48 and the cylinder 12 is a branch line 50 which leads to the mixing means 24. Branch line 50 is provided with a check valve 52 which permits fluid to flow only in the direction of the arrow (i.e., into the mixing means).

As can be appreciated, during reciprocation to the left of the piston of cylinder 10 causes the piston of cylinder 12 to likewise move to the left and to withdraw liquid from the supply 46 through line 44 to the cylinder l2. Thereafter, movement of the piston of cylinder 10 to the right causes simultaneous movement of piston 12 which in turn pumps a fixed quantity of the second fluid through line 50 to the mixing means 24.

As can be understood, by properly sizing the cylinders l0 and 12 any relative proportions of the first and second fluids could be supplied to the mixing means 24. In the subject embodiment, however, an adjustable means is provided in the connecting means 14 so that the length of the stroke or piston movement of cylinder 12 can be readily adjusted relative to the length of stroke of the piston of cylinder 10. These means could take many forms but as shown comprise a lost motion connection 54. Connection 54 includes a housing or body 56 which is positively connected to the end of piston rod 16. Piston rod 18 is slidably received through the outer end of housing 56 and, at its end has a disc or enlargement 58. A removable plate 60 is positioned within the housing 56. As is apparent, during movement of piston rod 16 to the right member 58 is not engaged until piston rod 16 has moved a substantial distance to the right to bring surface 62 of plate 60 into engagement with member 58. Thereafter, piston 12 will move to the right with piston rod 16. By varying the thickness of plate 60 the amount of movement undergone by the piston of cylinder 12 can be readily varied to vary the relative quantities of the two liquids. Note, for example, that by reducing the thickness of plate 60 the length of movement of piston rod 18 will be substantially reduced relative to that of piston rod 16. Correspondingly, increasing the thickness of plate 60 will increase the movement of piston rod 18 relative to piston rod 16. If plate 60 is of a thickness to completely fill the inner chamber of housng 56 the movement of piston rod 18 will be exactly equal to the movement of piston rod 60. Thus, merely by supplying a number of plates 60 of varying thickness the relative proportions of the fluids can be quickly changed without any major change in the overall system.

As will become apparent, many types of controls could be used for the system.

In the subject embodiment, the pilot valve 32 is a fluid actuated type and is arranged to be shifted in timed relationship with the movement of piston 16 by an air controlled assembly 65. The air control assembly 65 includes a line 66 which is connected to a source of compressed air through a standard air shutoff valve 68 and air filter 70 to a small, mechanically operable valve 72 having a discharge line 74 connected to the operator of the pilot valve 32. In a first position of movement of valve 72 air is directed from line 66 through the valve to line 74 to shift the pilot valve 32 to the left as in the solid line position. Movement of the valve 72 in the opposite direction connects the line 74 through the vent outlet with the atmosphere. In the subject embodiment the valve 72 is shifted between its two positions by having its operator 75 positioned between a pair of upwardly extending tabs or the like 76 and 78 carried on the connecting means 14. It should be understood that the valve 72 could be operated in other ways so long as it is operated in proper time relationship with the movement of piston rod 16.

FIG. 2 illustrates an embodiment which differs only slightly from that described with reference to FIG. 1. Accordingly, like reference numerals differentiated from the FIG. 1 embodiment by the addition of a prime suffix have been used to identify the same components. The description of one such FIG. 1 element is to be taken as equally applicable to the corresponding FIG. 2 element unless otherwise noted. In particular, FIG. 2 differs from the FIG. 1 embodiment primarily in the method of controlling the pilot valve 32. In this embodiment, pilot valve 32 is a fluid actuated valve but is controlled by the first fluid which is tapped off from supply line 26' through a line 80 which connects through valve 72' with line 81 leading to the operating end of pilot valve 32'. Line 82 is, however, connected directly to the mixing chamber 13. Thus, the small portion of the first fluid which is utilized to actuate the pilot valve 32' is directed to the mixing chamber 24 upon reversal of valve 72. This must be taken into account when adjusting the relative proportions of the two fluids.

Although not previously discussed, the mixing means 24' is a relatively simple unit. In particular, as shown in FIG. 1, it comprises an outer housing 84 having a discharge line 86 extending therefrom. Lines 40 and 42 discharge into the housing 84. Extending longitudinally within the housing 84 is an internal tube 88 having an extensively perforated wall. The end 90 of tube 88 is plugged and the opposite end is connected to receive the discharge of the second fluid coming through line 50. As can be appreciated, the perforated wall or baffle provided by tube 88 causes the second fluid to be dispersed throughout the interior of housing 84 and pro vides good mixing with the first fluid entering from lines 40 and 42 to assure that the mixture leaving line 86 is fully and completely mixed.

FIG. 3 illustrates a typical installation in which the proportioning systems of FIGS. 1 and 2 could be used. The major components of the proportioning system of FIG. 1 are indicated as being enclosed in a housing identified by the reference numeral 100. The water supply line 26 is shown extending to the proportioning system. Associated with the system is a drum 102 of the second fluid. The outlet 104 of drum 102 is preferably connected through a quick release connection 106 with a line 108 leading to a tank 110. Tank 110 serves as source 46 and is connected to line 44 as shown. A float controlled valve 112 is arranged to interrupt flow through line 26 (see FIG. 1) whenever the level of fluid within tank 110 drops below a predetermined level. This will shut down the entire proportioning system by stopping the flow of compressed air to the pilot valve 32. Similarly, in FIG. 2, valve 112' is closed by low level to stop the flow of water to the unit and thereby shut it down. The discharge line 86 through which the proportioned mixture exits from the proportioning unit 100 is directed to a mixture holding tank 114. Tank 114 provides a storage tank for the proportioned fluid mixture and can be connected directly to other process lines or merely drawn off manually as needed. Carried within tank 114 is a float which serves to control a valve 1 16. Referring to FIG. 1 it will be noted that valve 116 is located in line 66 and closes upon reaching a maximum level within tank 114. This similarly shuts down the proportioning system by topping the flow of compressed air to the pilot valve 32. Similarly, in the FIG. 2 embodiment valve 116' closes to shut off the flow of water thereby shutting the system down upon reaching a high level in tank 114.

The invention has been described in great detail sufficient to enable one of ordinary skill in the art to make and use the same. Obviously, modifications and alterations of the preferred embodiment will occur to others upon a reading and understanding of the specification and it is my intention to include all such modifications and alterations as part of my invention insofar as they come within the scope of the appended claims.

What is claimed is:

1. An apparatus for providing a closely proportioned mixture of at least a first and a second liquid comprismg:

a first double acting fluid cylinder having a first piston and a piston rod; a positive displacement piston pump; interconnecting means connecting said piston rod with said piston pump whereby movement of said first piston produces pumping movement of said supply and discharge means for supplying said first fluid under pressure to said first cylinder and discharging it therefrom, said supply and discharge means including control means for shifting the supply of said first fluid between opposite sides of said f'u'st piston to produce continuous reciprocation of said piston;

means for connecting a source of said fluid to said fluid mixing means receiving the discharges from said first fluid cylinder and said pump; and,

wherein said interconnecting means include an adjustable lost motion connection between said piston rod and said pump.

2. An apparatus for providing a closely proportioned mixture of at least a first and second liquid comprising:

a double acting fluid cylinder having a piston mounted for reciprocation therein and a piston rod extending outwardly from at least one end thereof;

a second fluid cylinder having a piston mounted therein and a piston rod extending outwardly from at least one end thereof;

means interconnecting the piston rods of said first and second cylinders for producing movement of said second cylinder in response to movement of said first cylinder;

first supply and discharge means for supplying said first fluid under pressure to said first cylinder and discharging it therefrom, said supply means including control means responsive to movement of at least one of said piston rods for causing said first fluid to be alternately supplied to opposite sides of the piston of said first cylinder and discharged from the other side thereof;

second supply and discharge means connected with said second cylinder for connecting said second cylinder with a source of said second fluid and permitting discharge of said second fluid from said second cylinder to a discharge line, said supply and discharge means including valve means whereby reciprocatory movement of said piston of said second cylinder withdraws said second fluid from the source thereof and pumps it to said discharge line;

a fluid mixer means;

fluid lines connecting the discharge from both said first and second cylinders to said fluid mixer means; and,

said interconnecting means comprising an adjustable means for permitting the length of reciprocation of said piston in said second cylinder to be varied relative to the length of the reciprocation of said piston in said first cylinder to thereby vary the relative proportions of said first and second fluids discharged to said fluid mixer.

3. The apparatus as defined in claim 2 wherein said adjustable means comprise an adjustable lost motion connection.

4. The apparatus as defined in claim 2 wherein said mixer means comprises a chamber having a perforated baffle plate and wherein said discharges from said first and second cylinders are separately supplied to opposite sides of said baffle plate.

5. The apparatus as defined in claim 2 wherein said control means include a pilot valve adapted to shift the supply of said first fluid between opposite sides of said piston of said first cylinder.

6. The apparatus of claim 5 wherein said pilot valve is fluid actuated.

7. The apparatus as defined in claim 6 wherein said pilot valve is actuated by said first fluid.

8. The apparatus as defined in claim 6 wherein a supply of actuating fluid to said pilot valve is controlled by a valve operated from at least one of said piston rods.

9. The apparatus as defined in claim 1 wherein said control means include a pilot valve adapted to shift the supply of said first fluid between opposite sides of said piston of said first cylinder.

10. The apparatus of claim 1 wherein said pilot valve is fluid actuated.

11. The apparatus as defined in claim 10 wherein said cylinder. 

1. An apparatus for providing a closely proportioned mixture of at least a first and a second liquid comprising: a first double acting fluid cylinder having a first piston and a piston rod; a positive displacement piston pump; interconnecting means connecting said piston rod with said piston pump whereby movement of said first piston produces pumping movement of said pump; supply and discharge means for supplying said first fluid under pressure to said first cylinder and discharging it therefrom, said supply and discharge means including control means for shifting the supply of said first fluid between opposite sides of said first piston to produce continuous reciprocation of said piston; means for connecting a source of said fluid to said pump; fluid mixing means receiving the discharges from said first fluid cylinder and said pump; and, wherein said interconnecting means include an adjustable lost motion connection between said piston rod and said pump.
 2. An apparatus for providing a closely proportioned mixture of at least a first and second liquid comprising: a double acting fluid cylinder having a piston mounted for reciprocation therein and a piston rod extending outwardly from at least one end thereof; a second fluid cylinder having a piston mounted therein and a piston rod extending outwardly from at least one end thereof; means interconnecting the piston rods of said first and second cylinders for producing movement of said second cylinder in response to movement of said first cylinder; first supply and discharge means for supplying said first fluid under pressure to said first cylinder and discharging it therefrom, said supply means including control means responsive to movement of at least one of said piston rods for causing said first fluid to be alternately supplied to opposite sides of the piston of said first cylinder and discharged from the other side thereof; second supply and discharge means connected with said second cylinder for connecting said second cylinder with a source of said second fluid and permitting discharge of said second fluid from said second cylinder to a discharge line, said supply and discharge means including valve means whereby reciprocatory movement of said piston of said second cylinder withdraws said second fluid from the source thereof and pumps it to said discharge line; a fluid mixer means; fluid lines connecting the discharge from botH said first and second cylinders to said fluid mixer means; and, said interconnecting means comprising an adjustable means for permitting the length of reciprocation of said piston in said second cylinder to be varied relative to the length of the reciprocation of said piston in said first cylinder to thereby vary the relative proportions of said first and second fluids discharged to said fluid mixer.
 3. The apparatus as defined in claim 2 wherein said adjustable means comprise an adjustable lost motion connection.
 4. The apparatus as defined in claim 2 wherein said mixer means comprises a chamber having a perforated baffle plate and wherein said discharges from said first and second cylinders are separately supplied to opposite sides of said baffle plate.
 5. The apparatus as defined in claim 2 wherein said control means include a pilot valve adapted to shift the supply of said first fluid between opposite sides of said piston of said first cylinder.
 6. The apparatus of claim 5 wherein said pilot valve is fluid actuated.
 7. The apparatus as defined in claim 6 wherein said pilot valve is actuated by said first fluid.
 8. The apparatus as defined in claim 6 wherein a supply of actuating fluid to said pilot valve is controlled by a valve operated from at least one of said piston rods.
 9. The apparatus as defined in claim 1 wherein said control means include a pilot valve adapted to shift the supply of said first fluid between opposite sides of said piston of said first cylinder.
 10. The apparatus of claim 1 wherein said pilot valve is fluid actuated.
 11. The apparatus as defined in claim 10 wherein said pilot valve is actuated by said first fluid.
 12. The apparatus as defined in claim 10 wherein a supply of actuating fluid to said pilot valve is controlled by a valve operated from at least one of said piston rods.
 13. The apparatus as defined in claim 2 wherein the piston in said first cylinder reciprocates a constant distance irrespective of the setting of said adjustable means and wherein said adjustable means varies only the length of reciprocation of said piston in said second cylinder. 